[Impeller] implement mask blur for textures

Author: gaaclarke

impeller/aiks/aiks_blur_unittests.cc

@@ -644,5 +644,22 @@ TEST_P(AiksTest, GaussianBlurStyleOuter) {
   ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
 }
 
+TEST_P(AiksTest, GaussianBlurStyleInnerTexture) {
+  Canvas canvas;
+  canvas.Scale(GetContentScale());
+  Paint paint;
+  paint.color = Color::Green();
+  paint.mask_blur_descriptor = Paint::MaskBlurDescriptor{
+      .style = FilterContents::BlurStyle::kNormal,
+      .sigma = Sigma(30),
+  };
+  std::shared_ptr<Texture> boston = CreateTextureForFixture("boston.jpg");
+  canvas.DrawImage(std::make_shared<Image>(boston), {200, 200}, paint);
+  Paint red;
+  red.color = Color::Red();
+  canvas.DrawRect(Rect::MakeXYWH(0, 0, 200, 200), red);
+  ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
+}
+
 }  // namespace testing
 }  // namespace impeller

impeller/aiks/canvas.cc

@@ -650,14 +650,30 @@ void Canvas::DrawImageRect(const std::shared_ptr<Image>& image,
     return;
   }
 
-  auto contents = TextureContents::MakeRect(dest);
-  contents->SetTexture(image->GetTexture());
-  contents->SetSourceRect(source);
-  contents->SetStrictSourceRect(src_rect_constraint ==
-                                SourceRectConstraint::kStrict);
-  contents->SetSamplerDescriptor(std::move(sampler));
-  contents->SetOpacity(paint.color.alpha);
-  contents->SetDeferApplyingOpacity(paint.HasColorFilter());
+  auto texture_contents = TextureContents::MakeRect(dest);
+  texture_contents->SetTexture(image->GetTexture());
+  texture_contents->SetSourceRect(source);
+  texture_contents->SetStrictSourceRect(src_rect_constraint ==
+                                        SourceRectConstraint::kStrict);
+  texture_contents->SetSamplerDescriptor(std::move(sampler));
+  texture_contents->SetOpacity(paint.color.alpha);
+  texture_contents->SetDeferApplyingOpacity(paint.HasColorFilter());
+
+  bool needs_color_filter = paint.HasColorFilter();
+  if (needs_color_filter) {
+    auto color_filter = paint.GetColorFilter();
+    if (texture_contents->ApplyColorFilter(
+            color_filter->GetCPUColorFilterProc())) {
+      needs_color_filter = false;
+    }
+  }
+
+  std::shared_ptr<Contents> contents = texture_contents;
+  if (paint.mask_blur_descriptor.has_value()) {
+    contents = paint.mask_blur_descriptor->CreateMaskBlur(
+        texture_contents,
+        needs_color_filter ? paint.GetColorFilter() : nullptr);
+  }
 
   Entity entity;
   entity.SetBlendMode(paint.blend_mode);

impeller/aiks/paint.cc

@@ -121,6 +121,24 @@ std::shared_ptr<Contents> Paint::WithColorFilter(
                                               absorb_opacity);
 }
 
+std::shared_ptr<FilterContents> Paint::MaskBlurDescriptor::CreateMaskBlur(
+    std::shared_ptr<TextureContents> texture_contents,
+    const std::shared_ptr<ColorFilter>& color_filter) const {
+  auto mask = std::make_shared<SolidColorContents>();
+  mask->SetColor(Color::White());
+  std::optional<Rect> coverage = texture_contents->GetCoverage({});
+  std::shared_ptr<Geometry> geometry = Geometry::MakeRect(coverage.value());
+  mask->SetGeometry(geometry);
+  std::shared_ptr<FilterContents> blurred_mask =
+      FilterContents::MakeGaussianBlur(FilterInput::Make(mask), sigma, sigma,
+                                       Entity::TileMode::kDecal, style,
+                                       geometry);
+
+  return ColorFilterContents::MakeBlend(
+      BlendMode::kSourceIn,
+      {FilterInput::Make(blurred_mask), FilterInput::Make(texture_contents)});
+}
+
 std::shared_ptr<FilterContents> Paint::MaskBlurDescriptor::CreateMaskBlur(
     std::shared_ptr<ColorSourceContents> color_source_contents,
     const std::shared_ptr<ColorFilter>& color_filter) const {

impeller/aiks/paint.h

@@ -13,6 +13,7 @@
 #include "impeller/entity/contents/contents.h"
 #include "impeller/entity/contents/filters/color_filter_contents.h"
 #include "impeller/entity/contents/filters/filter_contents.h"
+#include "impeller/entity/contents/texture_contents.h"
 #include "impeller/entity/entity.h"
 #include "impeller/entity/geometry/geometry.h"
 #include "impeller/geometry/color.h"
@@ -43,6 +44,10 @@ struct Paint {
         std::shared_ptr<ColorSourceContents> color_source_contents,
         const std::shared_ptr<ColorFilter>& color_filter) const;
 
+    std::shared_ptr<FilterContents> CreateMaskBlur(
+        std::shared_ptr<TextureContents> texture_contents,
+        const std::shared_ptr<ColorFilter>& color_filter) const;
+
     std::shared_ptr<FilterContents> CreateMaskBlur(
         const FilterInput::Ref& input,
         bool is_solid_color) const;